As it is known, one of the most commonly used solutions for the coupling between fluids consists in establishing, in one of the said conduits and as a terminal thereof, a threaded head which is aided by a matching threaded sleeve, so that the said sleeve is capable of adapting and securing a second conduit to the said head, with a tight coupling between these elements, generally obtained by the deformation of a sealing gasket.
As mentioned, this solution is one of the most commonly used for coupling fluid conduits because, since the handlings are quick and simple, there is neither a need for the pipes or conduits to be cut at the exact measurements as the coupling system enables substantial clearances to be absorbed, nor is specialised personnel required to carry out the coupling which only requires, for an optimum functionality, an assurance that the sleeve has been conveniently threaded, to its maximum, to the head.
However, this solution presents in practice, at least in determined cases, problems as to uncoupling, such as for example when the installation or a part thereof is subjected to vibrations which could cause the automatic unscrewing of the sleeve, or when this can be produced by water hammers, or by any other effect capable of producing the said unscrewing. Another problem posed by this solution consists in that the installation, and specifically the coupling points between the pipes or conduits, may be tampered with and there are no means for avoIding or at least controlling them.